Raking device for furnace grates



arch 8, 1938., E. LUDI ET AL BAKING DEVICE FOR FURNACE GRATES mmsm 2Sheets-Sheet 1 Filed July 29, 1936 March 193. E. LUDl' ET AL BAKINGDEVICE FOR FURNACE GRATES Filed July 29. 1936 2 Sheets-Sheet 2 PatentedMar. 8, 1938 Ernst Ludi,- Solothurn,

and Justus Burger,

Zurich, Switzerland; said Ludi assignor to said Burger Application July29,

1936, Serial No. 93,258 V In France August 10, 1935 2 Claims.

The invention relates to a raking device for furnace grates and moreparticularly to the class of raking devices comprising rows or series ofrake-blades adapted to enter between the grate bars and means for movingthe blades .up and down, so as to loosen the fuel and bring the cinderand the ashes through the grate.

One object of the invention is to provide a new and improved rakingdevice of the class set forth which is simple and durable inconstruction and easily manipulated to insure proper raking of the fueland to bring down the cinder without loss of fuel.

The invention consists of novel features and parts and combinations ofthe same as will be fully described hereinafter and then pointed out inthe claims.

Several practical embodiments of the invention are shown in theaccompanying drawings forming part of this specification in whichsimilar characters of reference indicate corresponding parts in all theviews.

Fig. 1 is a sectional elevation of the fire box of a furnace with theimprovements applied.

Fig. 2 is a sectional elevation on line II-II of Fig. 1,

Fig. 3 illustrates a raking blade of modified construction in a, planview.

Figs. 4 and 5 show a modified construction in 30 front elevation and ina ground plan respectively.

Fig. 6 illustrates a modification of the device shown in Figs. 4 and 5,in a front view and showing the interconnection of the blades.

Figs. 7 and 8 illustrate a further embodiment of the invention in frontelevation and in a ground plan respectively,

Fig. 9 is a front elevation of a modified arrangement of the blades withreference to each 40 other.

The fire box B of the furnace is of the usual construction and may be ofany size, the improvement is adapted for use in connection with avariety of furnaces. Grate bars 8 of suitable 45 cross-section arearranged in the lower portion of the furnace. In the ash pit P under thegrate bar 8 a shaft l is rotatably mounted in bearings 2 and 2' arrangedon opposite ends of the grate and running in the middle of the grate.

50 On the shaft I toothed blades 5 are arranged one for each openingbetween two consecutive grate bars 8. Each blade 5 comprises two wingsBI, 82, the upper edges of which are provided with teeth 83, 84 ofvarying size. The outer edges 55 85 are serrated. The dimensions of thewings are such that each of the two wings cleans one half of an openingbetween two grate oars. By rocking the shaft i one or the other of thewings BI, 82 enters the corresponding grate opening, all the teeth 83,85 may be brought topass over the upper face of the grate and to enterthe fire bed to agitate the fuel on the top of the grate and to readilycut any clinker that may rest in cakes on the grate. The blades 5 areprovided with holes 12. When the blades 5 pass into the fire bed, piecesof clinker pass. into the said holes l2 and are brought down into theash pit by the reversal of the blade movement. The shaft l is of squarecross-section, each blade 5 is held between two adjustable set-rings 3,4 fixed to shaft I by set screws. To rock the shaft l a crank-handle 9is provided which is removably fixed on the shaft i and which is outsidethe fire box. The blades 5 are wholly below the grate, some teeth 83being the only parts of the blades that extend through or into thegrate. The blades 5 do not hinder the ashes from falling through thegrate into the ash pit, moreover they do not prevent the access of airto the fuel on the grate and reach not into the red hot fuel. Theserrated faces of the blades 5 and the holes l2 thereof engage clinkersnear the ends of the grate openings and tear it down into the ash pit.

In Fig. 3 a modified construction of the shaped element is shown. Theblade l4 comprises two wings which are in one line and which have astraight upper edge on which the teeth are arranged. A row of holes [2is arranged near the upper edge. The dimensions are such that the teethdo not project above the grate 8, if the blade is not in operation.When. the latter is rocked only one side of each blade l4 enters thefuel. The two sides of the grate are worked one after the other.

The construction shown in Figs. 4 and 5 comprises two shafts 20 and 2|running parallel to each other and being arranged near the side walls ofthe fire box. The blades 22 working in the openings of the grate 8 arealternately attached to the shafts 20, 2|. Each blade 22 is locatedunder a gap in the grate. The upper edge of each blade 22 is providedwith teeth adapted to brake through the cinder or slack. In each blade arow of holes I2 is arranged. On each shaft 20, 2! an arm 35, 3! isrigidly fixed. The arms 35, 3| are interconnected by the rod 25. To thesquare ends of the shafts 20, 2| the crank lever may be attached and byturning one of the shafts 25, 2! the other will be rocked. The blades 22enter the gaps in the grate alternately. In the position of rest, theblades 22 are well within the gaps and well below the grate surface,leaving sufiicient space for the air to enter the bed of fuel.

In Fig. 6 a modified construction is shown. The shafts 2|, 2| areinterconnected by a rod 21 which is linked to the arms 33, 34,projecting on different sides of the shaft. In each gap of of the gratea blade 26 of the shafts 20, 2| is arranged. The blades are only halfthe length shown in Figs. 4 and 5. By rocking done by the shafts 20, 2|the blades 26 go up and down simultaneously. The blades 26 are eacharranged with a plurality of holes l2 working in the manner aforesaid.

A still further construction is shown in Figs. 7 and 8. The blades 28,28' are arranged on a common shaft l arranged below the bar 8 in the ashpit. The blades 28, 28' are well below the grate surface. The upperedges of each blade is provided with teeth and each blade is providedwith a plurality of holes I2. Consecutive blades 28, 28 work on theright or left hand side of shaft Each blade 28, 28 works only one sideof the grate.

In Fig. 9 blades are arranged on a common shaft l which runs in thecentre of the grate 8 and well below it. The blades 35 are provided ontwo opposite edges with teeth, moreover several rows of holes |2 arearranged running concentrically to shaft By rocking shaft the one or theother edge is brought in engagement with the gaps of the grate 8, asshown by broken lines in Fig. 9. In all the cases the holes l2 bringdown the cinder into the ash pit.

What we claim is:

1. In combination with the grate bars of a furnace, blade shapedelements oscillatably mounted below said bars in alignment with thespaces between the bars, the upper edges of said blade shaped elementsbeing formed as a series of inverted V-shaped teeth, said blade shapedelements having clinker receiving holes for purposes described.

2. In combination with the bars of a grate, of at least one shaftrockably mounted below the bars, an actuating device for said shaft, andraking blades carried by said shaft and aligning with the spaces betweenthe grate bars so that upon actuation of said shaft said blades. may beraised through the spaces between the bars, said blades having theiractive edges provided with sharpened serrations and having a set ofclinker receiving holes adjacent said serrations for purposes described.

ERNST LUDI. JUSTUS BURGER.

